JPH0356446A - Preparation of diterephthalate based on degradative esterexchange of scrapped or unused terephthalic polyester - Google Patents

Abstract

PURPOSE: To recycle a scrap or virgin terephthalate polyester into a terephthalate diester readily used as a plasticizer, etc., in one step and at a low cost by degradative transesterification with a specific higher alcohol.

CONSTITUTION: A terephthalate polyester is reacted with preferably an excess amount of a 6-20C higher mol.wt. alcohol or a mixture thereof preferably under a pressure of from a partial vacuum of 23 inch/Hg to 30 psi at a temperature of 160-260°C to obtain the aimed compound of the formula (wherein R and R' are each a 6-20C linear, branched or cyclic aliphatic group, an aromatic group, alkaryl or aralkyl) as easily filtrable liquid or an easily liquefiable product from scrap materials, etc., of terephthalate polyesters such as polyethylene terephthalate used for the preparation of carbonate soft drink bottles and the like advantageously at a low cost without necessitating an expensive reactor.

COPYRIGHT: (C)1991,JPO

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a process for producing terephthalic acid diesters by disintegration transesterification of terephthalic acid polyester products. The reactants used for this process are primarily terephthalate polyester products, preferably scrap terephthalate polyester raw materials, such as polyethylene terephthalate (PET) crystalline polyethylene terephthalate (CPET), glycol modified polyethylene terephthalate copolyester (PETG), polybutylene terephthalate (PBT), polycyclohexane dimethylene terephthalate (PCT), and PC
T acid and glycol modified copolyesters (each PC
TA and PCTG). This process yields terephthalic acid diesters, which are low to medium viscosity oils or waxes that are useful as plasticizers and possibly as processing aids and/or general purpose lubricants. The plasticizer is
It can immediately be used to produce products useful for the plastics industry.

[Background of the invention]

PET, CPET, PETG, PBT and PC
Terephthalate polyester resins such as T are thermoplastic polymers widely used in the plastics industry. PET and PETG are used for all kinds of films,
Used in the manufacture of bottles and plastic containers. Virgin PET and PETG resins have been recognized as good for food packaging; PET is widely used in the manufacture of both carbonate soft drink and alcoholic beverage bottles. It is also used in the production of cloth and textile materials.

CPET and PCTA can be opened on both sides (dua
It is used for manufacturing l-ove-nable food trays. Filled PET and PBT resins are used in the manufacture of automobile body panels, fenders, bumpers and grills; relays, iron handles, lawn mower housings, etc. The main problem of remanufacturing terephthalate polyester is
When heated in the presence of moisture, the polyester partially hydrolyzes to form some free glycol and terephthalic acid in the molten polymer. Polyester is therefore very dry during processing, typically 50pp to prevent any hydrolysis.
It must contain less than m water. Coincidentally, these materials often partially hydrolyze during each processing cycle, thus limiting the use of PET in the food packaging area to strictly virgin materials.

With the increasing use of polyester terephthalate biochemicals, major waste disposal and cost problems have been encountered by both manufacturers and consumers. PET and CPET are currently the most widely used of all terephthalate polyesters. These compounds include carbonate. It is used to make consumer products such as bottles for soft drinks and alcoholic beverages, and double-sided openable food trays. Typical scrap polyester products are shown in Table 1.

PET CPET PETG PBT Carbonate Soft drink bottle Beer, wine or licker bottle Bottle packaging film for food products like mustard (MYLARf”) Photography/X-ray film Cloth/Fyhar (DACRONiM, TERYLEN
E") Automobile fender (BEXLOY) Food tray that can be opened on both sides Bottle for personal hygiene such as shampoo or gargling detergent Food product Automobile bumper Automobile grill ★Distributor Cap PCTA ★Packaging Film ★Double-Sided Ovenable Food Tray PCT ★High Temperature Design Components There are currently many effective means to recycle or disintegrate/depolymerize polyester terephthalate. P.E.
T-soft drink bottles are currently being recycled, but with existing prior art methods, this material is extremely wasteful to provide pure raw materials used in products such as carpet linings, pot scrubbers, fiber fills, etc. Clean (bottle caps, paper or plastic labels, adhesives and high density polyethylene OIDPE)
There should be no contamination of any kind, such as shockproof pace caps. Cleaning/color separation methods are expensive and add significant cost to stirrup PET. If it is not cleaned, contaminated PET may only be used in low value, non-critical applications. On the other hand, clean PET can potentially be recycled many times. However, during each recycling/processing step, the polyester is further hydrolyzed to the point that after several recycling "cycles" the polyester disintegrates, exhibits significant loss of mechanical properties, and becomes an undesirable product. Ru.

When a food product is cooked in a CPET double-sided ovenable tray, the polymer is subjected to moderate heat for a relatively long period of time in the presence of a substantial amount of moisture that is released from the food product. This thermal history is similar to the hydrolysis caused by the moisture present during cooking.
) causes the CPET to collapse to the point where it exhibits a significant loss of mechanical properties. Cooked foods in CPET also result in polymer contamination and/or discoloration. Therefore, C.P.E.
The decay and discoloration of T makes it an undesirable material to recycle, and currently no recycling efforts are being made for CPET.

These undesirable materials are used in low value, non-critical applications such as fiber filling in pillows and sleeping bags, or they are also used in the preparation of high molecular weight polymers in the presence of monomers to produce lower molecular weight polymers. It can be recycled by partially depolymerizing. These types of methods are disclosed in US Pat. No. 3,037,048.

In U.S. Pat. No. 3.037.048, Lo tz
is scrap P such as filament, film, cloth, etc.
Discloses a method in which ET products are recycled to regenerate the compound dimethyl terephthalate (DMT). This method involves depolymerization and transesterification of PET in the presence of methanol to produce DMT.

Additionally, U.S. Patent No. 4.5 issued to Cudmore
No. 78.502 discloses the use of PET scrap to recover ethylene glycol and either terephthalic acid or dimethyl terephthalate. The method is hydrolytic or methanolic (a+etha
depolymerization of a slurry of scrap PET with subsequent crystallization of the desired product. U.S. Patent No.
The disclosure of No. 4,578,502 is limited to the production of dimethyl terephthalate. In fact, column 3 of this document, 2
Lines 2-28 state that it is not preferable to use an alcohol with a higher molecular weight than methanol. U.S. Patent No. 3,037,048 (2 pages, 64 lines)
and U.S. Pat. No. 4,578.502 (page 3, 5
In order to obtain value-added products from scrap polyterephthalate using the method referenced in lines 8-59), the use of an extremely high pressure reactor is necessary and therefore requires a major capital investment for equipment. It should be noted that this includes

Therefore, most PET/polyester recycling methods using transesterification currently known in the prior art mainly involve
The aim is to produce starting materials that can be used in the synthesis of new terephthalic acid products. It would therefore be of interest to provide a one-step process for the recycling of polyester terephthalates that yields products that can be readily used in the plastics industry or other fields. plasticizer, lubricant,
Waxes and the like are good examples of these useful products where plasticizers are ready-to-use products in the plastics industry. Plasticizers are critical in the production of some plastic products. For example, dioctyl terephthalate (DOTP) is particularly useful for the PvC industry. Esters of this type can primarily be synthesized by reacting terephthalic acid with a suitable alcohol. Unfortunately, in this case the esterification reaction is very slow, making the process economically undesirable. Instead, 2
- Transesterification of dimethyl terephthalate to DOTP by reaction with ethylhexanol is an interesting reaction that yields DOTP fairly quickly.

Therefore, an alternative means of suitable recycling that yields products of good commercial value is highly desirable. SUMMARY OF THE INVENTION In accordance with the present invention, there is provided a method for making a compound having the following general formula (I).

In formula (I), the substituents R and R' are the same or different and are straight chain, branched or cycloaliphatic groups, aromatic groups,
Represents an alkaryl group or an aralkyl group, and each group is
It has 6 to 20 carbon atoms. Preferably R and R' are the same or different and represent straight-chain or branched alkyl groups having 6 to 20 carbon atoms. The method is
reacting a terephthalic acid polyester green bottom with a high molecular weight alcohol or a mixture of high molecular weight alcohols having 6 to 20 carbon atoms in the presence of a catalyst, and recovering a compound of formula (I). .

Also within the scope of this invention is a method of recycling filled or unfilled scrap polyterephthalate to diester terephthalate. The method uses filled or unfilled scrap terephthalic polyester
High molecular weight alcohols having 6 carbon atoms or 6 each
reacting with a mixture of high molecular weight alcohols having ~20 carbon atoms in the presence of a catalyst at temperatures ranging from 160 to 26 Q'C and recovering the desired terephthalic acid diester.

Preferably, the source of the terephthalate ester is scrap terephthalate, although it is understood that any suitable source of terephthalate polyester (virgin, scrap or off-spec material) can be used in the context of the present invention. It is from a polyester product. The carbon atom content of the alcohol used in the process of the invention corresponds to the desired carbon atom content of the substituents R and R'.

It has therefore been discovered that scrap terephthalic acid polyester raw materials can be successfully recycled by transesterification with higher alcohols to yield valuable compounds. Preferably scrap PET.
Terephthalic acid polyesters such as PETG, CPIET or PBT can be recycled into desired products useful in the plastics industry.

In the context of the present invention, the term "recycle" as used herein refers to PET, PETG, CPET.
PBT or PCT and its copolyester PCT
A and P. It should be noted that scrap material such as CTG is intended to define a method in which it is used as a starting material for producing terephthalate esters such as plasticizers. For example, plasticizers such as dioctyl terephthalate (DOTP) can be produced using the method of the present invention at a cost comparable to that of currently available methods. The method of the invention is described, for example, in U.S. Pat. No. 4,578.50.
Considering the fact that the teachings of relevant literature on the recycling of PET, such as No. 2, clearly lead to the use of higher alcohols in reactions involving PET scrap,
Provides clear and unexpected benefits in the recycling of terephthalic acid polyester biomaterials.

Additionally, the process of the invention may be carried out in standard esterification reactors operating either at atmospheric pressure, partial vacuum or slightly overpressure, i.e., about 30 ps i or less. This provides a further improvement over prior art methods which usually require expensive high pressure reactors. It is also important to note that the raw materials obtained by the method of the present invention are liquid or easily liquefied by slight heating and are therefore easily filtered so that they are not contaminated (paper, caps, HDPE, etc.).
) Also includes scrap terephthalate polyester. This is because filtering low viscosity liquids is much easier than filtering high viscosity polymer melts. The possibility of using contaminated scrap considerably reduces the cost of recycled polyterephthalate and thus of the products obtained therefrom.

The advantages of the method of the invention will be more readily explained by reference to the following description.

[Detailed description of the invention]

The present invention relates to a method for producing terephthalic acid diester. The process uses PET used in bottles, photographic/
It is useful for recycling scrap polyterephthalate resins such as T and PBT. Generally speaking, the method of the present invention operates at temperatures of 160-260°C.
, preferably at temperatures varying between 185 and 240 °C, with straight-chain, fractionated or cycloaliphatic alcohols, or with aromatic, alkaryl alcohols, having a carbon atom content in the range from 6 to 20. or transesterification of terephthalic acid polyester products with aralkyl alcohols. The choice of alcohol obviously depends on the desired end product, and although straight-chain or branched alcohols having 6 to 20 carbon atoms are preferred, a wide range of alcohols may be used in the present invention. It should be understood that used in context. It should be mentioned that since the transesterification reaction is carried out with a catalyst, any suitable esterification or transesterification catalyst may be envisaged. Tin-based catalysts such as tin oxalate are preferred in the context of the present invention.

The temperatures at which transesterification of most terephthalic acid polyesters occurs are relatively high. It's usually 185~
The range is 240°C. However, many suitable alcohols that can be used in the process of the invention have boiling points below the desired transesterification temperature. This small difficulty can be overcome by slightly pressurizing the reactor or by adding an appropriate amount of the final product to the initial reaction mixture to raise the total boiling point. In some instances, however, it is also necessary to carry out the method under vacuum. Preferably, the reaction is carried out under partial vacuum 23'/Hg up to a pressure of 30 psi.

It should be mentioned that in some instances it is desirable to use mixtures of alcohols to carry out the method of the invention. In the case of alcohol mixtures containing two alcohols, three different compounds are obtained, one with both substituents R and R' carrying the alkyl/allyl moiety of the primary alcohol, and one with both substituents R and R' One species with substituted iR and R' has an alkyl/allyl moiety of the secondary alcohol and one species with substituents R and R'
Species will have different alkyl/allyl groups. The proportion of alcohol that forms the desired alcohol mixture will vary depending on the target composition of the final product.

There are two types of transesterification reactors to be used in the present invention for producing terephthalate esters: i) pressure reactors or ii) esterification reactors operating at atmospheric pressure. i. and this type of reactor is used when the boiling point of the alcohol or mixture of alcohols is below the optimum reaction temperature. The pressure reactor can be heated to, for example, 250°C and 400°C.
Dean & Stark of c} 5 connected to a wrap or any device used to perform the same function.
It consists of a 00cc container. This trap may be connected to a condenser to aid in the removal of glycol byproducts.

Typically, 0.25 molar equivalents (approximately 50 g) of shredded scrap PET are mixed with 1.0 molar equivalents of N (approximately 130 g
) alcohol and 0.3g tin catalyst with 500c
into the reactor c. Fill the Dean & Stark trap with 200 g water and 200 g alcohol. This assembled pressure reactor is 28 to 29 inches H
Evacuate to a vacuum level of 1.5 g and fill with inert carbon dioxide gas to a pressure of 5-10 psi. This reactor is 185-24
Heating to a temperature in the range of 0°C, preferably 205-235°C, for a period of 4 to 12 hours, preferably 4 to 7 hours, depending on the type of alcohol used. During the reaction process, reaction by-products, such as ethylene glycol, are evaporated.

It should be noted that removing glycol and/or adding excess alcohol accelerates the transesterification reaction. Excess, preferably 100 percent excess, of alcohol is used to promote the reaction since bubbling of the inert gas normally used to direct the vapor to the condenser does not occur in the reactor.

Removal of ethylene glycol from the alcohol/glycol condensate (which has been evaporated) is carried out using a suitable amount of water ranging from 5 to 400 cc, but preferably from 150 to 250 cc, using a 400 cc Dean A Stark} wrap or similar function. Any substance that is soluble in glycols and not alcohols having 6 to 20 carbon atoms, which is achieved by being present in any equipment used to carry out the It should be mentioned that at the end of the reaction the evaporated glycol is used in the context of Dean
& Stark is present in solution in water contained within the trap. Also, approximately 0.25 moles of the desired terephthalic acid diester, approximately corresponding to the number of molar equivalents of PET initially placed in the reactor, along with the initial 100 percent excess, residual glycol, and alcohol overflowing from the Dean & Stark trap are reacted. Found in containers.

11#' Esul and this type of reactor may be used for alcohols or mixtures of alcohols having boiling points within the operating range of the reaction. Alternatively, alcohols or mixtures of alcohols having boiling points below the optimum operating temperature may be used in the apparatus if appropriate amounts of the final product are added to raise the boiling point within the operating temperature range.

This reactor is typically a 500cc Dean &
It consists of a 5 l five-necked round bottom reaction vessel fitted with a Stark trap or any device used to perform a similar function followed by a 400 mm double jacketed condenser.

To minimize loss of alcohol and/or glycol, the vapors exiting the top of the condenser are passed through a cold trap cooled with dry ice and then through a Friedrich condenser. Return all condensate to Dean & Stark plastic wrap. The reactor is not pressurized and is operated at atmospheric pressure or under partial vacuum.

Typically, 2.5 molar equivalents (approx.
0-1800 g) of alcohol (20 percent excess) and 1.5 g of tin catalyst.

500cc Dean Stark} 5 laps
Fill with 0-450 cc of water, preferably 250-350 cc of water and 200 g of alcohol. This reactor was heated to 165 to 26 mm while continuously flowing inert carbon dioxide.
Heat to 0°C for 3-6 hours (depending on the type of alcohol used). How much glycol byproduct De
an & S, tark } is removed to the water layer within the wrap. A partial vacuum may be applied to aid in the reflux of the alcohol and thus the removal of the glycol.

At the end of the reaction, all the evaporated glycol is in solution in water in the trap. Also, approximately 2.5 moles of the desired terephthalic acid diester, approximately corresponding to the number of mole equivalents of PET initially placed in the reactor, residual glycol and Dean along with the initial 20 percent excess alcohol.
& Stark } Alcohol overflowing from the wrap can be seen in the reaction vessel.

Typical examples of raw substrates that may be obtained using the method of the present invention are di-n-hexyl terephthalate, dioctyl terephthalate, di-n-octyl n-decyl terephthalate, diisononyl terephthalate, diisodecyl terephthalate, di-n-tridecyl Contains n-pentadecyl terephthalate and diisoeicosyl terephthalate.

The following examples are included to explain the invention in more detail rather than to limit its scope.

Examples 1-7 illustrate the production of terephthalate esters using scrap PET as the feedstock.

Shredded Scruff from Clear Bottles of Soft Drinks”
100 g of PET (0.52 monolequivalent), 128 g of n-hexanol (1.25 mol), and 0.3 g of stannous oxalate were placed in a 500 cc pressure vessel.
Dean & Star
k) In the trap, 206 g of water and 206 g of n-
Added hexanol. The reactor was heated to 8 ps with carbon dioxide.
i (0.56 kg/c! I1), then heated from room temperature to 207° C. over 3 hours and 20° C. Gas chromatography analysis of the final raw material showed the presence of DNHTP.

Steam distillation (stripping) of DNHTP under reduced pressure
Residual n-hexanol and ethylene glycol were removed from this ester. The distillation vessel was heated from room temperature to approximately tso'c for 3 hours. The acidity equivalent of the raw material before washing was 0.95 .mu./KOH/g of product. A total of 107 g (0.32 mol) of final biomass was recovered after washing, drying, and filtering the ester. This indicates an overall yield of 61%. The final raw product was a wax at room temperature with a melting point range of 56-59°C.

The recovered glycol by-product has a refractive index of 1 at 23°C.
．． It was 4298.

1B Scrap PET (clear soft drink bottles) was reacted with 2-ethylhexanol. See Example 1 for a general overview of the procedure. For reaction conditions, see Table 2.
Please refer to See Table 3 for diester properties.

Scrap PET (green soft drink bottles) was reacted with isononyl alcohol. See Example 4 for a general overview of the procedure. See Table 2 for reaction conditions.

430 g (2.24 molar equivalents) of shredded scrap PET (clear soft drink bottles), 848 g (5.36 moles) of isodecanol and 0.98 g of stannous oxalate are placed in a 5 l reaction vessel. I put it in. 300 g of water and 18
8g of isodecanol was added. Inert carbon dioxide (
The reaction mixture was heated from room temperature to about 229°C over a period of 2 hours and maintained at about 229°C for an additional 4 hours under a continuous flow of bubbling in). Gas chromatography analysis of the final raw material showed the presence of DIDTP. Residual isodecanol and ethylene glycol were removed from this ester by steam distillation (stripping) of DIDTP under reduced pressure. The distillation vessel was heated from room temperature to 147'C over a period of 6 hours, after which 978g (2.19 moles) of the desired raw material was recovered, giving a yield of 98% after stripping.
%. The acidity equivalent of this product before washing was 0.22 -KOH/g. The ester was washed, dried and filtered. The acid value of the final raw material was 0.09 -KOH/g, the density at 23°C was 0.971 g/cc, and the refractive index at 23°C was 1.4914.

Scrap PET (transparent soft drink bottles)
It was reacted with a 50/50 mixture of n-octanol and n-decanol, commercially available under the tradename lfol 810. See Example 4 for a general overview of the procedure.

See Table 2 for reaction conditions. See Table 3 for diester properties. The resulting raw material was waxy at room temperature and had a melting point in the range of 33-34°C.

Scrap PET (transparent soft drink bottles) made by Hoshi,
It was reacted with a 70/30 mixture of n-1 ridecanol and n-pentadecanol, commercially available under the trade name xxal L 1315. See Example 4 for a general overview of the procedure. See Table 2 for reaction conditions.

See Table 3 for diester properties. The resulting product was a wax at room temperature with a melting point in the range of 45-46°C.

Extract scrap PET (transparent soft drink bottles)
It was reacted with isoeicosyl alcohol, commercially available under the trade name xal 20 (isoarachidyl) alcohol.

See Example 4 for a general overview of the procedure. See Table 2 for reaction conditions. See Table 3 for diester properties.

Examples 8 and 9 illustrate the preparation of terephthalate esters using scrap CPET as a feedstock.

Plastic B Scrap CPET (double ovenable food dish) was reacted with n-hexanol. See Example 1 for a general overview of the procedure. See Table 2 for reaction conditions. See Table 3 for diester properties.

Scrap CPET (double ovenable food dish) was reacted with isoeicosyl alcohol. See Example 4 for a general overview of the procedure. See Table 2 for reaction conditions.

See Table 3 for diester properties.

Examples 10 and 11 illustrate the preparation of terephthalate esters using PETG as the raw material.

Sand L'' PETG resin was reacted with n-hexanol. See Example 1 for a general overview of the procedure.

See Table 2 for reaction conditions. See Table 3 for the properties of the diesters. PETG resin was reacted with isoeicosyl alcohol. See Example 4 for a general overview of the procedure. See Table 2 for reaction conditions.

See Table 3 for diester properties.

Examples 12 and 13 illustrate the preparation of terephthalate esters using PBT as the raw material.

PBT resin was reacted with n-hexanol.

See Example 1 for a general overview of the procedure. See Table 2 for reaction conditions. See Table 3 for the properties of the diesters. PBT resin was reacted with isoeicosyl alcohol. See Example 4 for a general overview of the procedure. See Table 2 for reaction conditions.
Please refer to See Table 3 for the properties of the diesters. Table 2 Reactor charging and operating conditions DN used in Examples 1 to 13
HTP DOTP DINTP DIDTP 207±7 225±9 211±4 229±7 Pressure boost Atmospheric pressure Atmospheric pressure 61.4 62.1 Not obtained 97.9 Atmospheric pressure = The reactor is operated at atmospheric pressure.

Partial vacuum = 23 inches Hg of reactor (584 Hg)
Operate at partial vacuum up to.

Table 3 Properties of diesters D　N　II　TP DOTP DINTP DIDTP DNOro TP DNTDPDTP DIETP DNHTP DIETP DNHTP DIETP 10 11 Not obtained Not obtained 0.987 0.15 Not obtained Not obtained 0.971 0.09 Not obtained 0.24 Not obtained 0.24 0.922 0.12 Town [Kingyu Benthic Not obtained 0.24 0.916 0.32 ■Dekaoka zabu benthic Not obtained 0. 14 0.931 0.03 9l. 7 97.9 94.9 99.6 99.8 97.4 99.9 97.9 97.2 93.4 94.3 Table 3 (continued) Properties of diesters DNHTP DIETP 12 l3 Not obtained 0.55 0.924 0.03 94, 2 86.5

Claims (1)

[Claims] 1. The following general formula (I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (In the formula, R and R' are the same or different, and 6 to 2
It represents a straight-chain, branched or cycloaliphatic radical, an aromatic radical, an alkaryl radical or an aralkyl radical having 0 carbon atoms, each radical having from 6 to 20 carbon atoms. ) of the formula ( I ). 2. A process as claimed in claim 1, in which 2, R and R' are the same or different and represent a straight-chain or branched alkyl group having 6 to 20 carbon atoms. 3. The terephthalic acid polyester is combined with the high molecular weight alcohol or a mixture of high molecular weight alcohols and 30p
4. The method of claim 1, wherein the reaction is carried out under a partial vacuum of 23"/Hg up to a pressure of si. 4. An excess of said high molecular weight alcohol or mixture of high molecular weight alcohols is reacted with said polyester terephthalate. 5. The method of claim 1, wherein the reaction is carried out at a temperature in the range of 160 to 260° C. 6. The terephthalic acid polyester is combined with the high molecular weight alcohol or a mixture of high molecular weight alcohols; 7. The process of claim 1, wherein the reaction is carried out in a reactor comprising a reaction vessel and a Dean & Stark trap or any device that performs the same function. 7. A solvent for the glycol, an alcohol having from 6 to 20 carbon atoms. 7. The method of claim 6, wherein a material that is not soluble is added into the Dean & Stark trap, thereby increasing the removal of reaction by-products. 8. The method of claim 7, wherein the material is water. 9. The method of claim 7, wherein the material is water. The method of claim 1, wherein the terephthalic acid polyester is selected from the group consisting of polyethylene terephthalate, crystalline polyethylene terephthalate, glycol-modified polyethylene terephthalate copolyester, polybutylene terephthalate, and polycyclohexaline methylene terephthalate and its acid and glycol modified copolyesters. 10. The high molecular weight alcohol is selected from the group consisting of normal hexanol, 2-ethyl-hexanol, isononanol, isodecanol, isoeicosanol, normal octanol, normal decanol, normal tridecanol, and normal pentadecanol. 11. The method of claim 1. 11. The method of claim 1, wherein the mixture of high molecular weight alcohols is selected from the group consisting of a mixture of normal octanol and normal decanol and a mixture of normal tridecanol and normal pentadecanol. 12. The recovered compounds of formula I are di-n-hexyl terephthalate, di-octyl terephthalate, diisononyl terephthalate, diisodecyl terephthalate, di-n-octyl n-decyl terephthalate, di-n
- tridecyl n-pentadecyl terephthalate and diisoeicosyl terephthalate. 13. A process for recycling filled or unfilled scrap terephthalic acid polyester to terephthalic acid diester, the method comprising: recycling filled or unfilled scrap terephthalic acid polyester to a high molecular weight alcohol having from 6 to 20 carbon atoms; Said process comprising reacting a mixture of high molecular weight alcohols having ~20 carbon atoms in the presence of a catalyst at a temperature ranging from 160 to 260<0>C and recovering the desired terephthalic acid diester. 14. The terephthalic acid polyester is selected from the group consisting of polyethylene terephthalate, crystalline polyethylene terephthalate, glycol-modified polyethylene terephthalate copolyester, polybutylene terephthalate, and polycyclohexane dimethylene terephthalate and its acid and glycol modified copolymers. the method of. 15. The terephthalic acid polyester is combined with the high molecular weight alcohol or a mixture of high molecular weight alcohols, and 30
14. The method of claim 13, wherein the reaction is carried out under a partial vacuum of 23"/Hg to a pressure of psi. 16. The method of claim 15, wherein the terephthalic acid polyester is polyethylene terephthalate. 17. The terephthalic acid polyester is 16. The method of claim 15, wherein the polyester terephthalate is crystalline polyethylene terephthalate. 18. The method of claim 15, wherein the polyester terephthalate is a glycol-modified polyethylene terephthalate copolyester. 19. The polyester terephthalate is polybutylene terephthalate. 15. Method described.